Manchester United have approached Bayern Munich over a deal for centre-back Jerome Boateng, according to Sky in Germany.
The Premier League side believe their Bundesliga counterparts will ask for around £45m to allow the Germany international to leave the Allianz Arena.
It is understood that Boateng - who spent a season at United's bitter rivals Manchester City - could be open to a move to Old Trafford.
However, United are not the only side who are interested in the 73-cap international. Bayern chief executive Karl-Heinz Rummenigge said last month that Boateng was in talks with PSG.
He is the latest centre-back United have shown an interest in this summer, with Jose Mourinho looking to strengthen his defence before Thursday's transfer deadline.
They are still expected to bid for Leicester City's Harry Maguire this week, with Tottenham Hotspur's Toby Alderweireld and Barcelona's Yerry Mina other options.